/*
 * Copyright (C) 2010 Cyril Mottier (http://www.cyrilmottier.com)
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package greendroid.widget;

import android.database.DataSetObservable;
import android.database.DataSetObserver;
import android.view.View;
import android.view.ViewGroup;

/**
 * A SegmentedAdapter is a data source of a SegmentedHost/SegmentedHost.
 * 
 * @author Cyril Mottier
 */
public abstract class SegmentedAdapter {

	private final DataSetObservable mDataSetObservable = new DataSetObservable();

	/**
	 * How many segments have to be displayed
	 * 
	 * @return The number of segment displayed by the underlying SegmentedBar
	 */
	public abstract int getCount();

	/**
	 * Get the View associated to the segment at position <em>position</em>
	 * 
	 * @param position
	 *            The position of the item in the SegmentedAdapter
	 * @param parent
	 *            The parent that this view will eventually be attached to
	 * @return A View corresponding to the segment at the given position
	 */
	public abstract View getView(int position, ViewGroup parent);

	/**
	 * Get the title for the segment at position <em>position</em>
	 * 
	 * @param position
	 *            The position of the segment in the SegmentedBar
	 * @return A title for the segment at the given position.
	 */
	public abstract String getSegmentTitle(int position);

	/**
	 * Register an observer that is called when changes happen to the data used
	 * by this adapter.
	 * 
	 * @param observer
	 *            The object that gets notified when the data set changes.
	 */
	public void registerDataSetObserver(DataSetObserver observer) {
		mDataSetObservable.registerObserver(observer);
	}

	/**
	 * Unregister an observer that has previously been registered with this
	 * adapter via {@link #unregisterDataSetObserver(DataSetObserver)}
	 * 
	 * @param observer
	 *            The object to unregister
	 */
	public void unregisterDataSetObserver(DataSetObserver observer) {
		mDataSetObservable.unregisterObserver(observer);
	}

	/**
	 * Notifies the attached View that the underlying data has changed and
	 * should refresh itself.
	 */
	public void notifyDataSetChanged() {
		mDataSetObservable.notifyChanged();
	}
}
